The invention is based on a thermostatic valve with the aid of which mixed water can be discharged at a regulated temperature from a sanitary fitting. Such thermostatic valves conventionally have a temperature-sensitive regulating element, which moves axially a valve element as a function of the mixed water temperature. The valve element is constructed as a hollow cylinder. Between its axial end faces and a casing part are formed annular slots through which flow the hot and cold water. On displacing the valve element one slot becomes larger and simultaneously the other smaller. The two water flows are then mixed, so that the regulating element is exposed to the mixed water temperature.
Such a thermostatic valve is already known (DE 4423240). In this case the valve element is so positioned that the cold water flows through it. At the rear end of the valve element in the flow direction, i.e. in the vicinity of the slot for the hot water, is provided a solid plate positioned transversely to the flow direction. It forms a cross-sectional reduction for the cold water. As a result there is a strong vorticity or turbulence of the cold water and consequently a good, thorough mixing with the hot water. The aim is for the stretching material element to reliably respond to the actual mixed water temperature, but this is gained at the expense of a cross-sectional reduction.
A thermostatic mixing battery is also known (DE 2548650), in which the hot and cold water flow in axially and in opposite directions into the hollow cylindrical valve element and leave the latter roughly centrally. Here again at the end of one flow is provided a plate, which leads to a cross-sectional reduction.
The problem of the invention is to provide a thermostatic valve, in which a good mixing of the cold and hot water is obtained before reaching the temperature sensor and which is also built up with a limited pressure loss.
For solving this problem the invention proposes a thermostatic valve having a casing with an inlet for cold water, an inlet for hot water and an outlet for mixed water, a temperature sensor, which is exposed to the mixed water temperature, a valve element, which is movable by the temperature sensor as a function of the mixed water temperature for the oppositely directed opening or closing of two inlet ports, as well as with a mixing device for mixing the hot and cold water before reaching the temperature sensor, which is constructed in such a way that it at least partly radially deflects the flow of hot or cold water, in which the deflected flow strikes an axial flow of hot or cold water. Further developments of the invention form the subject matter of the appended claims, whose wording, like that of the abstract, is by reference made into part of the content of the present description.
Whereas in the known solutions the flows of hot and cold water mainly axially strike one another, so that they essentially stop one another, according to the invention one flow is deflected in such a way that it at least partly acquires a radial component. This radial component then encounters an axial flow, so that the mixing is brought about in a very satisfactory manner, but there is no mutual stopping of the flows.
According to a further development of the invention, the flow is subdivided into a radial part and an axial part. This also leads to a good turbulence and therefore mixing of the water flows without a pressure loss.
According to another further development of the invention, the deflection takes place within the hollow cylindrical valve element. Thus, the inflowing water is firstly axially directed and at least part of this axial flow is radially deflected and then strikes the second axial flow. Thus, mixing takes place at a point which is still clearly distanced from the temperature sensor.
According to the invention, for bringing about the desired mixing, the mixing device has a sleeve, which is provided with a free end around which the flow forms. As a result of the sleeve there is substantially no cross-sectional reduction.
According to a further development of the invention, in the vicinity of its free end, the sleeve has radial passage openings in the form of holes and/or slots through which the water can pass, so that as a result it forms the radial component.
The passage openings can in particular have a closed circumference. There can be several rows of passage openings, the number and size of said openings also being variable. It is also possible for part of the passage openings, e.g. slots, to extend to the free end of the sleeve, i.e. not to have a closed circumference.
According to the invention the mixing device can be constructed as an insert or extension of the casing.
According to yet another development of the invention, the sleeve is constructed in such a way that within the hollow cylindrical valve element the flow cross-section outside the sleeve and inside the sleeve is substantially the same. This also leads to uniform flow conditions and to a limited cross-sectional reduction.
If the sleeve is not to have the same cross-section at all points, according to the invention a cross-sectional change to the sleeve can take place gradually, i.e. no edges or steps are formed and instead there are curved or rounded transitions.
Further features, details and advantages of the invention can be gathered from the following description of a preferred embodiment of the invention and the attached drawing.